Insulating cover for bus bars



Apy 2G29, G. J. Mmmm '2,43%859 INSULATING COVER FOR BUS BARS Filed oct. P., 1945 Patented Apr. 2(1), 1948 INSULATING COVER FOR BUS BARS George J. Muller, Philadelphia, Pa., assignor to Taylor Fibre Company, Norristown, Pa., a corporation of Pennsylvania Application October 2, 1945, Serial No. 619,782 3 Claims. (Cl. 174-140) This invention relates to an improvement in insulating covers for conductor or bus bars having metalized inner surfaces for contact with the bars.

One of th'e objects of my invention is to provide a bus bar covering for eliminating the corona effect produced between the bus bar and its coverlng; due to the minute air gap between th'e covering and the bus bar, which corona produces carbon tracks on the surface o1 the insulating cover and in time causes insulation failure.

Another object of my invention is to provide a bus bar cover having a lining of copper or any other conducting metal, which can be grounded through a proper resistor to avoid the formation of a corona.

.another object of my invention is to provide a conducting lining which will be in contact with multitudinous places over the face of the bus bar and at the same time be perfectly anchored throughout its entire area to the covering.

Another object of my invenition is the provision oi' 'a method by which such covers can be made at a low cost and of the proper shape to be slipped on a bus bar, or a bar for conducting a high voltage current.

Having now described, in ageneral way, the nature and purpose of this invention, I will proceed for illustrative purposes, to a description of f a preferred embodiment thereof, with reference to the accompanying drawings, in which:

Figure l is a perspective view of a conductor bar having an insulating cover, in accordance with my invention.

Figure 2 is a perspective view oi a portion of mandrel, showing the method of winding a coverlng thereon, and9 Figure 3 is an end view of a completed cover.

in Figure i, the covering is designated by the reference character I0, on a conductor bar l2, and It designates the metal lining, embedded in the cover and contacting with the conductor bar l2,

In the form shown the conducting lining is formed of copper screening, and the covering ls formed as hereinafter described.

The reference character I6, designates a screw threaded through the covering and into contact with the metal lining, and connected to the screw between nuts i8, i8, is a grounded wire 20 having a resistor of the proper capacity therein, to prevent the formation of a corona between the conductor and the covering.

The metal lining is preferably formed of copper screening, although any other metal conduct- 2 ing screening, Pierced, or perforated sheet may be used for th'e lining.

The covering is formed by supporting a mandrel I2 the shape of the conducting bar I2 for winding strip material, then winding a turn' or two of dielectric material IIJ thereon, and then wrapping in the metal sheet I4 to produce an overlapping layer of the metal lining and then continuing the winding of dielectric material I0, until the required thickness of insulating wall is built up.

After the covering on the bar or mandrel has been built up. the mandrel is removed from the winding supports, and is then placed in a proper mold for compressing the dielectric material and after curing the cover is removed from the mandrel.

As the metal of the liner is harder or more dense than the dielectric material, portions thereor will cut through the dielectric material and will be exposed on the inner surface and will be in direct contact with the face of a bar over which it is slipped.

The cover may be made in different lengths and may be sawed into various lengths to cover the portions of bars to be insulated, and may then be drilled and tapped for a grounding screw or the lining may be grounded in any desired manner.

Any type of dielectric material which requires molding after wrapping may be used, but I preferably use apaper or fabric impregnated with a synthetic resin having insulating capacity, as, for example, a phenol formaldehyde type resin, and `which may be applied by wrapping and then formed in a mold under heat and pressure.

What l claim to secure by Letters Patent is:

l. An insulating covering for a conductor bar having a layer of dielectric material on the inner surface, a layer of copper screening on said innerlayer of dielectric material, a plurality of layers of dielectric material `on the screening portions of the screening extending through the inner layer of the dielectric and portions of the dielectric layers thereon, said layers being bonded to each other by an insulating cement.'

2. An insulating covering oi tubular shape for a conductor bar having a layer of dielectric material on the inner surface, a layer of foraminous conducting metal on said inner layer of dielectric material, a plurality of layers oi dielectric material wound on the layer of foraminous conducting metal bonded to each other by an insulating cement, portions ot the foraminous conducting metal extending through the inner layer of dielectric and portions oi the dielectric thereon,

3. An insulating covering o! tubular shape for a conductor bar having a layer of dielectric material on the inner surface, e, layer of foraminous conducting metal on said inner layer of dielectric material, a. plurality of layers of dielectric material wound on the layer of ioraminous conducting metal bonded to each other by an insulatingv foraminous sheet through the wall of the tube.

"MGEORGE J.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITEDKSTATES PATENTS Name VDate Watson Jan. 14, 1930 Faucett Oct. 29, 1935 Layton Mar. 26,' 1936 Morrison July 28, 1946 Boggs Mar. 23, 1937 Bormann Oct. 26, 1937 Knoderer Oct. 18, 1938 Scott et al Dec. 8, 1942 Youmans ,Feb. 23, 1943 Beede Mar. 30,1943 Smith 1 Oct. 3, 1994 Kauth, Aug. 14, 1945 Carlson Nov. 12, 1946 

